The present invention relates to pelletizers for thermoplastics, other plastics, and other materials.
Pelletizers for thermoplastics, other plastics, and other materials are well known to those skilled in the art. Pelletizers typically include a chamber, a rotating cutter within the chamber, a feed mechanism, and a collection chute. The feed mechanism delivers the thermoplastic to the rotating cutter, which cuts the thermoplastic into pellets which are collected in the collection chute. Examples of such technology may be seen, for example, in U.S. Pat. No. 7,124,972 dated Oct. 24, 2006 and U.S. Pat. No. 7,393,201 dated Jul. 1, 2008, both to Fetter.
Pelletizers are designed so that the vast majority of the pellets created by the cutting rotor travel directly into the collection chute. However, some of the pellets will circulate within the cutting chamber to come into contact with the rotating cutter once again. Sometimes this happens multiple times. This process is called “double cutting”, and it results in the creation of undesirable “fines”. Ultimately, the fines leave the cutting chamber through the collection chute. Because pellets of a uniform size are desired, the fines are essentially “contaminants”. Fines reduce the “yield”, the quality, and the value of the pelletized product.